In integrated circuits, the degree of integration is more and more increased and in the production of a semiconductor substrate of VLSI, processing of super-fine patterns made of line width having a half-micron or less has been required. For satisfying the requirement, the wavelength of a light exposure apparatus used for a photolithography is more and more shortened and at present, the use of a far ultraviolet light and an excimer laser (e.g., XeCl, KrF or ArF) has been investigated. Furthermore, the formation of finer patterns by electron beams or X-rays has been investigated.
Particularly, electron beam lithography is positioned in the next generation or the next but one generation pattern-forming technique, and developments of negative-working resist having high sensitivity and high resolution and excellent in reproducibility of beam shape have been eagerly desired. The reproducibility of beam shape is an important property for forming a desired pattern in variable-shaped direct imaging electron beam lithography. In especial, when crooked line patterns are imaged, it is important that the beam shapes can be reproduced at the crooked parts in the patterns formed, from the viewpoint of the post-step (super-fine processing of substrate).
As a resist material for such a purpose, a chemical amplification type resist mainly utilizing an acid catalyst reaction is used and as a negative-working resist, a chemical amplification resist composition containing as the main components, an alkali-soluble resin, an acid generator and an acid crosslinking agent is effectively used.
Regarding the acid generator, Japanese Patent Publication No. 3635/1996 discloses organic halogen compounds, Japanese Patent Laid-Open No. 52348/1990 discloses aromatic compounds substituted with Br or Cl, Japanese Patent Laid-Open No. 367864/1992 and Japanese Patent Laid-Open No. 367865/1992 disclose aromatic compounds having an alkyl or alkoxy group substituted with Br or Cl, Japanese Patent Laid-Open No. 150848/1990 and Japanese Patent Laid-Open No. 199770/1994 discloses iodonium compounds and sulfonium compounds, Japanese Patent Laid-Open No. 87746/1991 discloses haloalkane sulfonate compounds, Japanese Patent Laid-Open No. 210960/1992 and Japanese Patent Laid-Open No. 217249/1992 disclose diazodisulfone compounds or diazosulfone compounds, Japanese Patent Laid-Open No. 336454/1992 discloses Br- or I-substituted alkyltriazine compounds, Japanese Patent Laid-Open No. 291258/1992 discloses sulfonamide compounds and sulfonimide compounds, Japanese Patent Laid-Open No. 291259/1992 discloses sulfonic acid compounds of polyhydric phenols, Japanese Patent Laid-Open No. 291260/1992, Japanese Patent Laid-Open No. 291261/1992, and Japanese Patent Laid-Open No. 202320/1994 disclose naphthoquinonediazido-4-sulfonate compounds, Japanese Patent Laid-Open No. 210239/1993 discloses disulfone compounds, Japanese Patent Laid-Open No. 236024/1994 discloses N-oxyimidosulfonate compounds, and U.S. Pat. No. 5,344,742 discloses benzylsulfonate compounds.
Regarding the acid crosslinking agent, Japanese Patent Laid-Open No. 75652/1991, Japanese Patent Laid-Open No. 181277/1993 and Japanese Patent Laid-Open No. 146556/1995 disclose methoxymethylmelamine compounds, Japanese Patent Laid-Open No. 281455/1992, Japanese Patent Laid-Open No. 232702/1993 and Japanese Patent Laid-Open No. 83055/1994 disclose compounds having an alkoxymethyl ether group, Japanese Patent Laid-Open No. 281715/1993 discloses oxazine compounds, Japanese Patent Laid-Open No. 134412/1993 and Japanese Patent Laid-Open No. 3825/1994 disclose aromatic compounds having an alkoxyalkyl group, Japanese Patent Laid-Open No. 194838/1994 discloses trioxane compounds, and Japanese Patent Laid-Open No. 293339/1989 discloses alkoxymethyluryl compounds.
Moreover, Japanese Patent Laid-Open No. 43837/1997 discloses combinations of hydroxystyrene copolymer resins and basic compounds decomposable into neutral compounds by radiation, and Japanese Patent Laid-Open No. 125907/1999 discloses combinations of hydroxystyrene resins and compounds generating carboxylic acids having a high boiling point by radiation.
However, any combination of these compounds cannot satisfy a high sensitivity, a high resolution, and reproducibility of beam shape all together.